GLACIERS OF ALASKA 9
recent period began just after the Harriman Expedition's observations in June, 1899, and seems to have been initiated, and perhaps somewhat hastened, by the shaking during the severe Yakutat Bay earthquakes of September, 1899, but in large part as a result of the increased area of ice front exposed to iceberg discharge. The rapid retreat of Muir Glacier has resulted in the loss of much of its scenic beauty and in its relative inaccessibility to tourist steamers between 1899 and 1909 because of the increased amount of floating ice. This retreat is also dismembering the glacier systems so that the number of separate ice fronts is continually increasing.
Alexander Archipelago. Chicagof, Baranof, Kruzof, Admiralty, Kupreanof, and Prince of Wales Islands and the smaller islands of the Alexander Archipelago seem to have all been glaciated but only small glaciers are known to linger upon them. Brooks shows two small glaciers upon Baranof Island east of Sitkal on one of his maps and Knopf has alluded to several small glaciers here.2
Glaciers on Pacific Coast of Fairweather Range.* There are a number of ice tongues that flow south or west from the Fairweather Range either to Cross Sound and Icy Strait or to the Pacific. Among these is the Brady Glacier, a through glacier heading on the divide with Reid Glacier of Glacier Bay and having a length of 27 miles and a width of 2j to 6 miles. It is not tidal but ends within 2 miles of Taylor Bay. It advanced 5 miles between 1794 and 1894,4 and Muir reports that it was advancing and destroying trees in 1880.6
LaPerouse Glacier is a small piedmont glacier near the base of Mt. Fairweather, and and the only Alaskan ice tongue that enters the open ocean and discharges icebergs at present. It was visited and studied carefully by G. K. Gilbert in June, 1899,° when he found that it had retreated one or two hundred yards from a forest edge into which it was advancing in September, 1895, as shown by a photograph from a Fish Commission vessel. The junior author on October 5, 1904, and both of us in September, 1909, saw LaPerouse Glacier from a steamer close in shore and it had then retreated still farther from the forest than when Gilbert was there ten years before. The same was true in 1906 when the Wright brothers of the United States Geological Survey were there.' Between September 4, 1909, and June 10, 1910, when the junior author was fortunate enough to see the glacier from another vessel close inshore, the LaPerouse Glacier had advanced across the barren zone of three to six hundred feet observed by Gilbert, plus the thousand feet or so of additional retreat during the ensuing ten years, and was once more destroying the forest on both margins, as it had been fifteen years before.8 The glacier next east of LaPerouse had also retreated from a forest edge in 1899 but was not advancing in 1909 or 1910.
i Brooks, A. H., Professional Paper 45, U. S. Geol. Survey, 1906, PI. XII. «Bull. 504, U. S. Geol. Survey, 1912, pp. 10-11.
* U. S. Coast and Geod. Survey, Charts 3089, 8050, and 8304; Coast Pilot, Alaska, Part I, 1908, PI. opposite p. 184.
Atlas of Award, Alaskan Boundary Tribunal, Sheets 15,16, 19.
* Klotz, Otto, Geog. Journ., Vol. XIV, 1899, pp. 526-^528.
* Reid, H. F., Variations of Glaciers, Journ. Geol., Vol. V, 1897, p. 380. « Harriman Alaska Expedition, Vol. Ill, 1904, pp. 39-45.
* Personal Communication from P. E. Wright.
* Martin, Lawrence, Gletscheruntersuchungen langs der Ktlate von Alaska, Petermanns Geog. Mitt., Jahrgang 1912, Augustheft, p. 78; Journ. Geol., Vol. XIX, 1911, p. 457.